Tension structures are now well established as a way of covering large areas economically and many examples exist, perhaps the best known in Great Britain being the Millennium Dome. These structures normally have a fabric membrane stretched tightly between supporting members to form a roof. In smaller structures these supports are masts or steel arches but in larger structures, such as the Dome, the fabric may be stretched between cables which themselves are tensioned between the main supports. This is necessary because there is a practical limit to the size of fabric panel which may be used. Large tension structures are thus composed of main supports, a network of cables and the tensioned fabric.